Multicenter trial to test new liver transport system

Jan. 4, 2018, 9:15 AM

The growing list of patients needing liver transplants continues to outpace the number of available donor organs, but a new preservation and transport device for donor livers could possibly make a big difference.

Vanderbilt University Medical Center (VUMC) is among 15 centers — and the only institution in Tennessee — enrolling patients in a randomized, controlled study comparing the efficacy of traditional static cold storage to ex-vivo normothermic (normal body temperature) machine perfusion in liver transplantation.

The machine, the OrganOx metra, is a fully automated and transportable device that enables the liver to continue functioning during transport from the donor to the recipient by mimicking the human body.

“I believe perfusion is the future of organ transplantation,” said Sophoclis Alexopoulos, MD, chief of Vanderbilt’s Division of Hepatobiliary Surgery and Liver Transplantation.

“This technology has the potential to increase the donor pool as well as maximize recipient outcomes. This type of technology may allow us more time to schedule surgeries, examine the liver’s function and potentially decrease the injury associated with the current storage techniques.

“We will also be able to closely monitor the liver — how well blood is flowing throughout the organ, what the pH levels are and whether the liver is producing bile or not. It is this kind of data that may allow us in the future to potentially explore livers that we may not have considered for transplantation in the past.

The OrganOx metra device has the ability to preserve a liver for up to 24 hours outside the body in a condition suitable for transplantation, a feat unattainable with the standard preservation methods, said Alexopoulos.

The device continuously perfuses oxygenated blood and nutrition to the liver allowing for continuous monitoring of how the liver is functioning.

The machine has been studied extensively in the United Kingdom and Europe, where it is currently being used, said Alexopoulos.

The study will allow participating centers to compare the degree of injury of livers that are on the machine to the degree of injury of livers that are on cold storage. Injury is based on biochemical or blood tests.

“The longer we keep a liver on cold storage, the higher the enzymes may go after we transplant it, leading to more recipient complications,” said Alexopoulos. “We want to show that warm perfusion is better than cold static storage, with the hypothesis that machine perfusion livers are going to demonstrate less biochemical injury.”

Donor livers using the newest technology include those coming from older, brain death donors (age 40 and above) and donation after cardiac death (DCD).

Vanderbilt is one of the top 10 programs in the U.S. by volume, performing about 150 liver transplants a year and is on target for this kind of innovation, he added.

Recruiting patients has not been difficult.

“Vanderbilt gives patients the ability to participate in cutting-edge aspects of liver transplantation, and this device is just one example of that,” Alexopoulos said. “We are finding that patients are very excited about this trial.

“There are so many future possibilities that this kind of technology can bring. The potential to modulate or modify ex-vivo organs, the potential capability of rehabilitating damaged livers for transplantation and the possibility of modulating the immune profile of the liver to facilitate compatibility issues. As an academic medical center we have the resources to ask these questions and look for the answers.”

The multicenter study seeks to transplant 266 donor livers. Vanderbilt’s trial officially started in October with the enrollment of its first two liver transplant candidates.